feat: adding a schema command

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

pyproject.toml

@@ -142,6 +142,9 @@ build.targets.sdist.include = [
 ]
 version.source = "vcs"
 
+[tool.uv]
+environments = ["python_version >= '3.10'"]
+
 [tool.ruff]
 target-version = "py38"
 line-length = 120

src/tox/config/sets.py

@@ -3,7 +3,7 @@
 import sys
 from abc import ABC, abstractmethod
 from pathlib import Path
-from typing import TYPE_CHECKING, Any, Callable, Iterator, Mapping, Sequence, TypeVar, cast
+from typing import TYPE_CHECKING, Any, Callable, Generator, Iterator, Mapping, Sequence, TypeVar, cast
 
 from .of_type import ConfigConstantDefinition, ConfigDefinition, ConfigDynamicDefinition, ConfigLoadArgs
 from .set_env import SetEnv
@@ -33,6 +33,12 @@ def __init__(self, conf: Config, section: Section, env_name: str | None) -> None
         self._final = False
         self.register_config()
 
+    def get_configs(self) -> Generator[ConfigDefinition[Any], None, None]:
+        """:return: a mapping of config keys to their definitions"""
+        for k, v in self._defined.items():
+            if k == next(iter(v.keys)):
+                yield v
+
     @abstractmethod
     def register_config(self) -> None:
         raise NotImplementedError

src/tox/plugin/manager.py

@@ -42,6 +42,7 @@ def _register_plugins(self, inline: ModuleType | None) -> None:
             legacy,
             list_env,
             quickstart,
+            schema,
             show_config,
             version_flag,
         )
@@ -60,6 +61,7 @@ def _register_plugins(self, inline: ModuleType | None) -> None:
             exec_,
             quickstart,
             show_config,
+            schema,
             devenv,
             list_env,
             depends,

src/tox/session/cmd/schema.py

@@ -0,0 +1,112 @@
+"""Generate schema for tox configuration, respecting the current plugins."""
+
+from __future__ import annotations
+
+import json
+import typing
+from pathlib import Path
+from typing import TYPE_CHECKING
+
+import packaging.requirements
+import packaging.version
+
+import tox.config.set_env
+import tox.config.types
+from tox.config.sets import ConfigSet
+from tox.plugin import impl
+import tox.tox_env.python.pip.req_file
+
+if TYPE_CHECKING:
+    from tox.config.cli.parser import ToxParser
+    from tox.session.state import State
+
+
+@impl
+def tox_add_option(parser: ToxParser) -> None:
+    parser.add_command("schema", [], "Generate schema for tox configuration", gen_schema)
+
+
+def _process_type(of_type: typing.Any) -> dict[str, typing.Any]:
+    if of_type in {
+        Path,
+        str,
+        packaging.version.Version,
+        packaging.requirements.Requirement,
+        tox.tox_env.python.pip.req_file.PythonDeps,
+    }:
+        return {"type": "string"}
+    if of_type is bool:
+        return {"type": "boolean"}
+    if of_type is float:
+        return {"type": "number"}
+    if of_type is tox.config.types.Command:
+        return {"type": "array", "items": {"#ref": "#/definitions/command"}}
+    if of_type is tox.config.types.EnvList:
+        return {"type": "array", "items": {"type": "string"}}
+    if typing.get_origin(of_type) in {list, set}:
+        return {"type": "array", "items": _process_type(typing.get_args(of_type)[0])}
+    if of_type is tox.config.set_env.SetEnv:
+        return {
+            "type": "object",
+            "additionalProperties": {"type": "array", "items": {"type": "string"}},
+        }
+    if typing.get_origin(of_type) is dict:
+        return {
+            "type": "object",
+            "additionalProperties": {"type": "array", "items": _process_type(typing.get_args(of_type)[1])},
+        }
+    msg = f"Unknown type: {of_type}"
+    raise ValueError(msg)
+
+
+def _get_schema(conf: ConfigSet, path: str) -> dict[str, dict[str, typing.Any]]:
+    properties = {}
+    for x in conf.get_configs():
+        name, *aliases = x.keys
+        of_type = getattr(x, "of_type", None)
+        if of_type is None:
+            continue
+        desc = getattr(x, "desc", None)
+        try:
+            properties[name] = {**_process_type(of_type), "description": desc}
+        except ValueError:
+            print(name, "is unrecognised:", of_type)
+        for alias in aliases:
+            properties[alias] = {"$ref": f"{path}/{name}"}
+    return properties
+
+
+def gen_schema(state: State) -> int:
+    core = state.conf.core
+    properties = _get_schema(core, path="#/properties")
+
+    env_properties = _get_schema(state.envs["3.13"].conf, path="#/properties/env_run_base/properties")
+
+    json_schema = {
+        "$schema": "http://json-schema.org/draft-07/schema",
+        "$id": "https://github.com/tox-dev/tox/blob/main/src/tox/util/tox.schema.json",
+        "type": "object",
+        "properties": {
+            **properties,
+            "env_run_base": {"type": "object", "properties": env_properties},
+            "env_pkg_base": {"$ref": "#/properties/env_run_base"},
+            "env": {"type": "object", "patternProperties": {"^.*$": {"$ref": "#/properties/env_run_base"}}},
+        },
+        "#definitions": {
+            "command": {
+                "oneOf": [
+                    {"type": "string"},
+                    {
+                        "type": "object",
+                        "properties": {
+                            "replace": {"type": "string"},
+                            "default": {"type": "array", "items": {"type": "string"}},
+                            "extend": {"type": "boolean"},
+                        },
+                    },
+                ],
+            }
+        },
+    }
+    print(json.dumps(json_schema, indent=2))
+    return 0